Studies of solar intranetwork fields and current helicity in active regions

In this paper we begin with a brief review of the most recent observational studies of intranetwork elements. Next by analyzing well observed quantities of other magnetic elements, we suggest that the magnetic flux of all elements is proportional to its lifetime, mainly depending on each size. Then we present an empirical way to extrapolate the size and magnetic field of intranetwork elements, and find that their average size is about 210 km and the corresponding field strength is 350 G. Finally, our studies of current helicity in active regions are summarized as follows: (1) most of the active regions in solar cycle 22 follow the hemispheric helicity sign rule, and the evolution of surface large-scale current helicity has a good correlation with solar activity; (2) the active regions with reversed helicity sign tend to emerge at certain longitudes; (3) the rapid and substantial changes of current helicity in an area or in its vicinity are most likely to trigger flares. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved.